Communication method and apparatus

Abstract

A communication method and apparatus. In the method, a sparse DMRS pattern comprising Q (Q>3) CDM groups is designed on the basis of DMRS Type 2, expanding the number of CDM groups and reducing the frequency-domain resource density of each CDM group of a DMRS, thereby facilitating reduction of transmission resource overhead of the DMRS.

Description

Communication method and apparatus

[0001] This application claims priority to the Chinese patent application No. 202410866435.8, filed on June 28, 2024, entitled "Communication method and apparatus", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of communication technology, and in particular to a communication method and apparatus. BACKGROUND

[0003] A demodulation reference signal (DMRS) can be used for channel estimation of a physical downlink shared channel (PDSCH) or a physical uplink shared channel (PUSCH). Currently, according to different DMRS port division, the configuration type of the DMRS can include configuration type 1 (Type 1) and configuration type 2 (Type 2), wherein the number of orthogonal DMRS ports and the time-frequency resource mapping rules supported by different configuration types are different. At present, for the configuration Type 2, the existing Type 2 configuration contains 3 code division multiplexing groups (CDM groups), and each CDM group occupies 4 resource elements (REs) on each resource block (RB). In some scenarios, for example, in the urban air mobility (UAM) scenario, there is often a direct path in the UAM scenario, so that the channel transmission delay spread is small. If the existing Type 2 configuration is directly used for channel estimation, there will be a large resource overhead. SUMMARY

[0004] The present application provides a communication method and apparatus, which is beneficial to reduce the transmission resource overhead of the DMRS.

[0005] The present application will be described from different aspects below. It should be understood that the implementation manners and beneficial effects of the different aspects below can be mutually referred.

[0006] In a first aspect, the present application provides a communication method, which can be applied to a terminal side, such as a terminal or a communication module in the terminal, or a circuit or chip (such as a Modem chip, also known as a baseband chip, or a system on chip (SoC) chip or a system in package (SIP) chip containing a modem core) responsible for communication functions in the terminal. Taking the case where the method is applied to a terminal, in the method, the terminal receives first indication information and second indication information, and then the terminal can receive or transmit DMRS according to the first indication information and the second indication information. The first indication information is used to indicate the number Q of code division multiplexing groups supported by the configuration type 2 of DMRS, and Q is an integer greater than 3. The second indication information is used to indicate the first code division multiplexing group number and the first DMRS port index, wherein the first code division multiplexing group number is the number of code division multiplexing groups that do not support DMRS and data multiplexing, and the first DMRS port index is the index of the scheduled DMRS port. The first code division multiplexing group number is an integer greater than or equal to 4 and less than or equal to Q, or the first code division multiplexing group number is an integer greater than or equal to 1 and less than or equal to Q. The number of first DMRS port indexes is at least one, and the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 4Q-1.

[0007] In the present application, different from the configuration scheme in the existing DMRSType 2 configuration which only contains 3 code division multiplexing groups (i.e. CDM group), the present application proposes a scheme that the DMRS Type 2 configuration can configure more than 3 CDM groups, for example, Q can be 6, 12 or 24, etc. Among them, the existing DMRS Type 2 configuration requires more RE resources, specifically, each CDM group occupies 4 REs on each RB. And the scheme of the present application based on the DMRS Type 2 configuration design with Q (Q>3) CDM groups can reduce the number of REs occupied by each CDM group on each RB, for example, when Q=6, each CDM group occupies 2 REs on each RB. For example, when Q=12, each CDM group occupies 2 REs on every 2 RBs (i.e. equivalent to each CDM group occupying 1 RE on each RB). For example, when Q=24, each CDM group occupies 2 REs on every 4 RBs (i.e. equivalent to each CDM group occupying 0.5 RE on each RB). That is, the present application designs a sparse DMRS pattern with Q (Q>3) CDM groups based on the DMRS Type 2, thus expanding the number of CDM groups and reducing the density of each CDM group of the DMRS in the frequency domain resources, thereby facilitating to reduce the transmission resource overhead of the DMRS.

[0008] In a possible implementation, the second indication information is carried in downlink control information (DCI), and the second indication information is an antenna port field, the antenna port field indicating a first index value, the first index value corresponding to the first code division multiplexing group quantity and the first DMRS port index.

[0009] In this implementation, the configuration of Q code division multiplexing groups based on the configuration type 2 of DMRS is adapted, and it is further proposed that the existing DCI antenna port field (for example, “Antenna Port(s)” field) can be multiplexed, and the reserved bits are used to indicate the first code division multiplexing group quantity and the first DMRS port index based on the existing DMRS port mapping table, which is beneficial to protocol compatibility and improves the applicability of the scheme.

[0010] In a possible implementation, in the case that the maximum length of the DMRS is 1, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 2Q-1. In this implementation, the number of available DMRS ports is increased, and optionally, it is also beneficial to protocol compatibility.

[0011] In a possible implementation, in the case that the maximum length of the DMRS is 2, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 4Q-1. In this implementation, the number of available DMRS ports is increased, and protocol compatibility is optionally facilitated.

[0012] In a possible implementation, the code division multiplexing group to which the first DMRS port index belongs is a scheduled code division multiplexing group, the scheduled code division multiplexing group is included in the Q code division multiplexing groups, and the value of the index of the scheduled code division multiplexing group is an integer greater than or equal to 0 and less than or equal to Q-1. In this implementation, protocol compatibility is facilitated.

[0013] In a possible implementation, the receiving or transmitting of the DMRS according to the first indication information and the second indication information includes:

[0014] determining, according to the first indication information and the second indication information, time-frequency resources and a DMRS sequence corresponding to the DMRS;

[0015] receiving or transmitting the DMRS sequence on the time-frequency resources.

[0016] In a possible implementation, the DMRS sequence on the time-frequency resources and the time-frequency resources respectively satisfy:

[0017] wherein the denotes the DMRS sequence on the time-frequency resources;

[0018] The k denotes a subcarrier index in the time-frequency resources.

[0019] The l denotes an orthogonal frequency division multiplexing, OFDM, symbol index in the time-frequency resources.

[0020] The p j denotes an index of an antenna port.

[0021] The μ denotes a subcarrier spacing.

[0022] The denotes a power scaling factor, and the is related to the first code division multiplexing group number.

[0023] The w f (k') denotes a frequency domain orthogonal cover code, OCC.

[0024] The w t (l') denotes a time domain OCC.

[0025] The r(2n+k') represents a pseudo-random sequence.

[0026] The represents a starting DMRS symbol index.

[0027] The l' represents a DMRS symbol relative index.

[0028] The v represents a number of the first DMRS port indexes.

[0029] The delta represents a subcarrier offset factor.

[0030] The Q is a number of code division multiplexing groups supported by a configuration type 2 of DMRS.

[0031] In this implementation, the configuration of Q code division multiplexing groups based on the configuration type 2 of DMRS is adapted, and a DMRS pattern resource mapping scheme is additionally added, and specifically, the DMRS sequence on the time-frequency resource and the time-frequency resource under the new configuration satisfy the above formulas, which is beneficial to reduce DMRS overhead and ensure protocol compatibility.

[0032] In a possible implementation, the satisfies:

[0033] The P represents a number of the first code division multiplexing groups.

[0034] In this implementation, the configuration of Q code division multiplexing groups based on the configuration type 2 of DMRS is adapted, and the value of a power scaling factor is additionally added, which is beneficial to protocol compatibility and improvement of applicability of the scheme, and also improves reliability of channel estimation based on DMRS.

[0035] In a possible implementation, the first DMRS port index corresponds to the delta, the w f (k') and the w t (l'); the delta is an integer greater than or equal to 0 and less than or equal to 2*(Q-1), and different DMRS ports in a code division multiplexing group to which the first DMRS port index belongs are orthogonal.

[0036] In this implementation, the configuration of Q code division multiplexing groups based on the configuration type 2 of DMRS is adapted, and the value of a frequency domain OCC and a time domain OCC determined by an antenna port in a PDSCH DMRS OCC mapping table is additionally added, which is beneficial to protocol compatibility and improvement of applicability of the scheme.

[0037] In a possible implementation, the method further includes:

[0038] transmit capability information, the capability information indicating that the terminal supports Q code division multiplexing groups of configuration type 2 based on DMRS.

[0039] In this implementation, the terminal reports its capability of supporting Q code division multiplexing groups of configuration type 2 based on DMRS, so that the access network device can make corresponding configuration based on the capability supported by the terminal, which is conducive to protocol compatibility and improves the applicability of the scheme.

[0040] In a possible implementation, the capability information is carried in a radio resource control (RRC) message or uplink control information (UCI).

[0041] In a possible implementation, the method further includes receiving request information, the request information being used to request the terminal to report the capability information. In this implementation, the access network device requests the terminal to report its supported capability, which can reduce the reporting times of the terminal, and thus is conducive to reducing the resource overhead of the terminal when reporting the capability.

[0042] In a possible implementation, the request information is carried in an RRC message or DCI.

[0043] In a possible implementation, the first indication information is carried in an RRC message. In this implementation, it is conducive to protocol compatibility.

[0044] In a second aspect, the present application provides a communication method, which can be applied to the network side, for example, an access network device on the network side or a component (for example, a circuit, a chip or a chip system, etc.) in the access network device. Taking the case where the method is applied to the access network device as an example, in the method, the access network device transmits first indication information, the first indication information being used to indicate the number Q of code division multiplexing groups supported by configuration type 2 of DMRS, the Q being an integer greater than 3; and the access network device transmits second indication information, the second indication information being used to indicate a first code division multiplexing group number and a first DMRS port index, wherein the first code division multiplexing group number is the number of code division multiplexing groups that do not support multiplexing of DMRS and data, the first DMRS port index is the index of a scheduled DMRS port, the first code division multiplexing group number is an integer greater than or equal to 4 and less than or equal to Q, the number of the first DMRS port index is at least one, and the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 4Q-1.

[0045] The first indication information and the second indication information are used for receiving or transmitting DMRS.

[0046] In a possible implementation, the second indication information is carried in a DCI, and the second indication information is an antenna port field, the antenna port field indicating a first index value, the first index value corresponding to the first number of code division multiplexing groups and the first DMRS port index.

[0047] In a possible implementation, in the case that the maximum length of the DMRS is 1, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 2Q-1.

[0048] In a possible implementation, in the case that the maximum length of the DMRS is 2, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 4Q-1.

[0049] In a possible implementation, the code division multiplexing group to which the first DMRS port index belongs is a scheduled code division multiplexing group, the scheduled code division multiplexing group being included in the Q code division multiplexing groups, and the value of the index of the scheduled code division multiplexing group is an integer greater than or equal to 0 and less than or equal to Q-1.

[0050] In a possible implementation, the method further includes:

[0051] receiving capability information, the capability information indicating that the terminal supports Q code division multiplexing groups of a DMRS-based configuration type 2.

[0052] In a possible implementation, the capability information is carried in an RRC message or UCI.

[0053] In a possible implementation, the method further includes:

[0054] sending request information, the request information being used to request the terminal to report the capability information.

[0055] In a possible implementation, the request information is carried in an RRC message or DCI.

[0056] In a possible implementation, the first indication information is carried in an RRC message.

[0057] In a third aspect, the present application provides a communication apparatus, which can be a terminal or a chip in a terminal. The communication apparatus includes:

[0058] a transceiver, configured to receive first indication information, the first indication information being used to indicate a number Q of code division multiplexing groups supported by a configuration type 2 of a demodulation reference signal (DMRS), the Q being an integer greater than 3;

[0059] The transceiving unit is configured to receive second indication information, the second indication information being used to indicate a first code division multiplexing (CDM) group number and a first DMRS port index, wherein the first CDM group number is a number of CDM groups that do not support multiplexing of DMRS and data, the first DMRS port index is an index of a scheduled DMRS port, the first CDM group number is an integer greater than or equal to 4 and less than or equal to Q, the number of the first DMRS port index is at least one, and the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 4Q-1.

[0060] The transceiving unit is configured to receive or transmit DMRS according to the first indication information and the second indication information.

[0061] In a possible implementation, the second indication information is carried in downlink control information (DCI), and the second indication information is an antenna port field, the antenna port field indicating a first index value, the first index value corresponding to the first CDM group number and the first DMRS port index.

[0062] In a possible implementation, in a case where the maximum length of the DMRS is 1, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 2Q-1.

[0063] In a possible implementation, in a case where the maximum length of the DMRS is 2, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 4Q-1.

[0064] In a possible implementation, a CDM group to which the first DMRS port index belongs is a scheduled CDM group, the scheduled CDM group being included in the Q CDM groups, and the value of an index of the scheduled CDM group is an integer greater than or equal to 0 and less than or equal to Q-1.

[0065] In a possible implementation, the communication device further includes a processing unit, and wherein:

[0066] The processing unit is configured to determine, according to the first indication information and the second indication information, time-frequency resources corresponding to the DMRS and a DMRS sequence.

[0067] The transceiving unit is configured to receive or transmit the DMRS sequence on the time-frequency resources.

[0068] In a possible implementation, the DMRS sequence on the time-frequency resources and the time-frequency resources respectively satisfy:

[0069] wherein the This refers to the DMRS sequence on the time-frequency resource;

[0070] The k represents the subcarrier index in the time-frequency resource;

[0071] The l represents the orthogonal frequency division multiplexing (OFDM) symbol index in the time-frequency resources;

[0072] The p j Indicates the index of the antenna port;

[0073] μ represents the subcarrier spacing;

[0074] The Represents the power scaling factor, the It is related to the number of the first code division multiplexed groups;

[0075] The w f (k′) represents the frequency domain orthogonal mask (OCC);

[0076] The w t (l′) represents the time-domain OCC;

[0077] The r(2n+k′) represents a pseudo-random sequence;

[0078] The Indicates the starting DMRS symbol index;

[0079] The l′ represents the relative index of the DMRS symbol;

[0080] v represents the number of the first DMRS port indexes;

[0081] The △ represents the subcarrier offset factor;

[0082] Q represents the number of code division multiplexing groups supported by DMRS configuration type 2.

[0083] In one possible implementation, the satisfy:

[0084] Wherein, P represents the number of the first code division multiplexed groups.

[0085] In one possible implementation, the first DMRS port index corresponds to △, and the w f (k′) and the w t (l′); the △ is an integer greater than or equal to 0 and less than or equal to 2*(Q-1), and the different DMRS ports within the code division multiplexing group to which the first DMRS port index belongs are orthogonal.

[0086] In a possible implementation, the transceiver is configured to send capability information, where the capability information indicates that the terminal supports Q code division multiplexing groups of configuration type 2 based on DMRS.

[0087] In a possible implementation, the capability information is carried in an RRC message or UCI.

[0088] In a possible implementation, the transceiver is configured to receive request information, where the request information is used to request the terminal to report the capability information.

[0089] In a possible implementation, the request information is carried in an RRC message or DCI.

[0090] In a possible implementation, the first indication information is carried in an RRC message.

[0091] In a fourth aspect, the present application provides a communication apparatus, which can be an access network device or a chip in the access network device. The communication apparatus comprises:

[0092] a transceiver configured to send first indication information, where the first indication information is used to indicate a number Q of code division multiplexing groups supported by configuration type 2 of a demodulation reference signal (DMRS), and the Q is an integer greater than 3;

[0093] the transceiver is configured to send second indication information, where the second indication information is used to indicate a first code division multiplexing group number and a first DMRS port index, the first code division multiplexing group number is a number of code division multiplexing groups that do not support multiplexing of DMRS and data, the first DMRS port index is an index of a scheduled DMRS port, the first code division multiplexing group number is an integer greater than or equal to 4 and smaller than or equal to Q, the number of the first DMRS port index is at least one, and the value of the first DMRS port index is an integer greater than or equal to 0 and smaller than or equal to 4Q-1;

[0094] The first indication information and the second indication information are used to receive or send DMRS.

[0095] In a possible implementation, the second indication information is carried in downlink control information (DCI), and the second indication information is an antenna port field, where the antenna port field indicates a first index value, and the first index value corresponds to the first code division multiplexing group number and the first DMRS port index.

[0096] In a possible implementation, in a case where the maximum length of the DMRS is 1, the value of the first DMRS port index is an integer greater than or equal to 0 and smaller than or equal to 2Q-1.

[0097] In a possible implementation, when the maximum length of the DMRS is 2, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 4Q-1.

[0098] In a possible implementation, the code division multiplexing group to which the first DMRS port index belongs is a scheduled code division multiplexing group, the scheduled code division multiplexing group is included in the Q code division multiplexing groups, and the value of the index of the scheduled code division multiplexing group is an integer greater than or equal to 0 and less than or equal to Q-1.

[0099] In a possible implementation, the transceiver is configured to receive capability information, and the capability information indicates that the terminal supports Q code division multiplexing groups of the DMRS-based configuration type 2.

[0100] In a possible implementation, the capability information is carried in an RRC message or UCI.

[0101] In a possible implementation, the transceiver is configured to send request information, and the request information is used to request the terminal to report the capability information.

[0102] In a possible implementation, the request information is carried in an RRC message or DCI.

[0103] In a possible implementation, the first indication information is carried in an RRC message.

[0104] In a fifth aspect, a communication apparatus is provided. The communication apparatus includes a processor and a transceiver. The processor and the transceiver are configured to perform the method in any of the first aspect to the second aspect, or the method in any of the possible implementation of any of the first aspect to the second aspect.

[0105] Optionally, the communication apparatus further includes a memory in which a computer program is stored. The processor and the transceiver are configured to invoke the computer program stored in the memory, so that the communication apparatus performs the method in any of the first aspect to the second aspect, or the method in any of the possible implementation of any of the first aspect to the second aspect.

[0106] In a possible design, the communication apparatus can be a chip or a device including the chip that implements the above method.

[0107] In a sixth aspect, a communication apparatus is provided. The communication apparatus includes a processor and an interface circuit. The interface circuit is configured to receive a signal from another communication apparatus outside the communication apparatus and transmit the signal to the processor, or send a signal from the processor to another communication apparatus outside the communication apparatus. The processor is configured to implement the method in any of the first aspect to the second aspect, or the method in any of the possible implementation of any of the first aspect to the second aspect, by means of a logic circuit or an execution of a code instruction.

[0108] In a seventh aspect, the present application provides a computer readable storage medium, having stored therein computer programs or instructions, which when executed by a computer, implement the method according to any one of the first aspect to the second aspect, or the method according to any possible implementation of any one of the aspects.

[0109] In an eighth aspect, the present application provides a computer program product, which when read and executed by a computer, causes the computer to perform the method according to any one of the first aspect to the second aspect, or the method according to any possible implementation of any one of the aspects.

[0110] In a ninth aspect, the present application provides a chip system, which comprises at least one processor and an interface, the processor being configured to read and execute instructions stored in a memory, which when executed, causes the chip to perform the method according to any one of the first aspect or the second aspect, or the method according to any possible implementation of any one of the aspects.

[0111] In a tenth aspect, the present application provides a communication system, which can comprise a terminal and an access network device. The terminal is configured to perform the method according to the first aspect or any possible implementation of the first aspect. The access network device is configured to perform the method according to the second aspect or any possible implementation of the second aspect. BRIEF DESCRIPTION OF DRAWINGS

[0112] Fig. 1 is a schematic diagram of an architecture of a communication system to which embodiments of the present application are applied;

[0113] Fig. 2 is a schematic diagram of a prior art DMRS pattern;

[0114] Fig. 3 is a schematic diagram of a flow of a communication method according to an embodiment of the present application;

[0115] Fig. 4 is a schematic diagram of a DMRS pattern of 6 CDM groups based on Type 2 according to an embodiment of the present application;

[0116] Fig. 5 is a schematic diagram of a DMRS pattern of 12 CDM groups based on Type 2 according to an embodiment of the present application;

[0117] Fig. 6 is a schematic diagram of a DMRS pattern of 24 CDM groups based on Type 2 according to an embodiment of the present application;

[0118] Fig. 7 is a schematic diagram of another flow of a communication method according to an embodiment of the present application;

[0119] Fig. 8 is a schematic diagram of a structure of a possible communication apparatus according to an embodiment of the present application;

[0120] FIG. 9 is a structural schematic diagram of a possible communication device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0121] The technical solutions in the embodiments of the present application will be clearly and completely described in combination with the drawings in the embodiments of the present application.

[0122] In the description of the present application, "first" and "second" are used only to distinguish different objects, and are not used to describe a specific order. In addition, unless otherwise specified, " / " means "or", for example, A / B can mean A or B. "And / or" in this document is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. In addition, "at least one" means one or more, and "multiple" means two or more. "At least one of the following" or the like means any combination of the items, including any combination of single item or multiple items. For example, at least one of a, b, or c can mean a, b, c; a and b; a and c; b and c; or a and b and c. Where a, b, and c can be single or multiple.

[0123] The terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device, etc. including a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed, or can optionally include other steps or units inherent to the process, method, product, or device, etc.

[0124] In the present application, the words "exemplary" or "for example" are used to mean serving as an example, instance, or illustration. Any embodiment or design scheme described as "exemplary", "for example" or "for instance" in the present application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Rather, the use of "exemplary", "for example" or "for instance" is intended to present concepts in a concrete manner.

[0125] It can be understood that in the present application, "when", "if" and "when" all refer to the device making corresponding processing under certain objective conditions, and are not limited to time, and do not require the device to have a judgment action when implemented, nor does it mean that there are other limitations.

[0126] In the present application, the element expressed by the singular is intended to represent "one or more", and not "one and only one", unless otherwise specified.

[0127] It can be understood that, in the embodiments of the present application, "A corresponds to B" means that A and B have a corresponding relationship, and B can be determined according to A. Determining B according to A does not mean that B is determined only according to A, but B can also be determined according to A and / or other information.

[0128] In order to better understand the embodiments of the present application, first, the system architecture related to the embodiments of the present application will be introduced as follows:

[0129] Please refer to FIG. 1, which is a schematic diagram of the architecture of a communication system to which the embodiments of the present application are applied. It should be noted that FIG. 1 is a possible and non-limiting system diagram. As shown in FIG. 1, the communication system 10 includes a radio access network (RAN) 100 and a core network (CN) 200, and optionally, the communication system 10 can also include the Internet 300. The RAN 100 includes at least one RAN node (such as 110a and 110b in FIG. 1, collectively referred to as 110) and at least one terminal (such as 120a-120j in FIG. 1, collectively referred to as 120). The RAN 100 can also include other RAN nodes, such as wireless relay devices and / or wireless backhaul devices (not shown in FIG. 1), etc. The terminal 120 is connected to the RAN node 110 in a wireless manner. The RAN node 110 is connected to the core network 200 in a wireless or wired manner. The core network element in the core network 200 and the RAN node 110 in the RAN 100 can be different physical devices respectively, or can be the same physical device integrated with the logical functions of the core network and the logical functions of the radio access network, or can be a physical device integrated with the functions of part of the core network elements and the functions of part of the RAN nodes 110. Terminals and terminals, and RAN nodes 110 and RAN nodes 110 can be connected to each other in a wired or wireless manner. FIG. 1 is only a schematic diagram, and the communication system can also include other network devices, such as wireless relay devices and wireless backhaul devices, which are not shown in FIG. 1.

[0130] The RAN 100 can be a 3rd generation partnership project (3GPP) related cellular system, such as a 4G, 5G mobile communication system, or a future-oriented evolved system (such as a 6G mobile communication system). The RAN 100 can also be an open radio access network (O-RAN or ORAN), a cloud radio access network (CRAN), or a wireless fidelity (WiFi) system. The RAN 100 can also be a communication system in which two or more of the above systems are integrated.

[0131] The RAN node 110, which can also be referred to as a radio access network device, an access network device, a RAN entity, or an access node, etc., forms part of the communication system, and is configured to facilitate wireless access to the communication system for terminals. The RAN nodes 110 in the communication system 10 can be of the same type or can be of different types. In some scenarios, the roles of the RAN nodes 110 and the terminals 120 are relative, e.g., the network element 120i in Figure 1 can be a helicopter or a drone, which can be configured to be a mobile base station, and for a terminal 120j accessing to the RAN 100 through the network element 120i, the network element 120i is a base station; but for the base station 110a, the network element 120i is a terminal. The RAN nodes 110 and the terminals 120 are sometimes referred to as communication devices, e.g., the network elements 110a and 110b in Figure 1 can be understood as communication devices with base station functionalities, and the network elements 120a-120j can be understood as communication devices with terminal functionalities.

[0132] In a possible scenario, the RAN node 110 can be a base station, an evolved NodeB (eNodeB), an access point (AP), a transmission reception point (TRP), a next generation NodeB (gNB), a next generation base station in a 6th generation (6G) mobile communication system, a base station in a future mobile communication system, or an access node in a WiFi system, etc. The RAN node 110 can be a macro base station (e.g., 110a in Figure 1), a micro base station or an indoor station (e.g., 110b in Figure 1), a relay node or a donor node, or a wireless controller in a CRAN scenario. Optionally, the RAN node 110 can also be a server, a wearable device, a vehicle or a vehicle-mounted device, etc. For example, the wireless access network device in a vehicle to everything (V2X) technology can be a road side unit (RSU). All or part of the functions of the RAN node 110 in this application can also be implemented by a software function running on hardware, or by a virtualized function instantiated on a platform (e.g., a cloud platform). The RAN node 110 in this application can also be a logical node, a logical module or software capable of implementing all or part of the functions of the RAN node 110.

[0133] In another possible scenario, a terminal is assisted by multiple RAN nodes 110 to implement wireless access in cooperation, and different RAN nodes 110 respectively implement part of functions of a base station. For example, a RAN node 110 can be a central unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU), etc. The CU and the DU can be separately arranged, or can also be included in the same network element, such as a baseband unit (BBU). The RU can be included in a radio frequency device or a radio frequency unit, such as a radio remote unit (RRU), an active antenna processing unit (AAU), or a remote radio head (RRH).

[0134] In different systems, the CU (or CU-CP and CU-UP), DU or RU can also have different names, but those skilled in the art can understand their meanings. For example, in an ORAN system, the CU can also be referred to as an O-CU (open CU), the DU can also be referred to as an O-DU, the CU-CP can also be referred to as an O-CU-CP, the CU-UP can also be referred to as an O-CU-UP, and the RU can also be referred to as an O-RU. For the convenience of description, the CU, CU-CP, CU-UP, DU and RU are taken as examples for description in this application. Any one of the CU (or CU-CP, CU-UP), DU and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0135] A terminal can also be referred to as a terminal device, user equipment (UE), mobile station, mobile terminal, etc. The terminal can be widely applied to various scenarios, such as device-to-device (D2D), vehicle to everything (V2X) communication, machine-type communication (MTC), internet of things (IOT), virtual reality, augmented reality, industrial control, automatic driving, remote medical treatment, smart power grid, smart furniture, smart office, smart wear, smart transportation, smart city, etc. The terminal can be a mobile phone, tablet computer, computer with wireless transceiver function, wearable device, vehicle, unmanned aerial vehicle, helicopter, airplane, ship, robot, mechanical arm, smart home device, etc. Embodiments of this application do not limit the device form of the terminal.

[0136] For ease of description, the following describes the base station as an example of the RAN node 110. The base station and the terminal can be fixed in position or mobile. The base station and the terminal can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; can also be deployed on water surface; can also be deployed on an airplane, a balloon and a man-made satellite. Embodiments of the present application do not limit the application scenarios of the base station and the terminal.

[0137] The roles of the base station and the terminal can be relative, for example, the helicopter or the unmanned aerial vehicle 120i in FIG. 1 can be configured as a mobile base station, and for the terminal 120j that accesses the wireless access network 100 through 120i, 120i is a base station; but for the base station 110a, 120i is a terminal, that is, 110a and 120i communicate through a wireless air interface protocol. Of course, 110a and 120i can also communicate through a base station-to-base station interface protocol, in which case, 120i is also a base station relative to 110a. Therefore, the base station and the terminal can be collectively referred to as a communication device, 110a and 110b in FIG. 1 can be referred to as a communication device with a base station function, and 120a-120j in FIG. 1 can be referred to as a communication device with a terminal function.

[0138] The base station and the terminal, the base station and the base station, and the terminal and the terminal can communicate through a licensed spectrum, can communicate through an unlicensed spectrum, or can communicate through both the licensed spectrum and the unlicensed spectrum; can communicate through a spectrum below 6 gigahertz (GHz), can communicate through a spectrum above 6 GHz, or can communicate through both the spectrum below 6 GHz and the spectrum above 6 GHz. Embodiments of the present application do not limit the spectrum resources used for wireless communication.

[0139] In embodiments of the present application, the functions of the base station can also be performed by a module (such as a chip) in the base station, or can be performed by a control subsystem containing the functions of the base station. The control subsystem containing the functions of the base station herein can be a control center in the above-mentioned application scenarios such as smart grid, industrial control, intelligent transportation and smart city. The functions of the terminal can also be performed by a module (such as a chip or a modem) in the terminal, or can be performed by a device containing the functions of the terminal.

[0140] In the present application, the base station sends downlink signals or downlink information to the terminal, and the downlink information is carried on the downlink channel; the terminal sends uplink signals or uplink information to the base station, and the uplink information is carried on the uplink channel. In order to communicate with the base station, the terminal needs to establish a wireless connection on the cell controlled by the base station. The cell that establishes a wireless connection with the terminal is called the service cell of the terminal. When the terminal communicates with the service cell, it will also be interfered by signals from the neighbor cell.

[0141] In order to facilitate the understanding of the related content of the embodiments of the present application, some knowledge / terminology needed by the schemes of the present application will be introduced below. It should be noted that these explanations are to make the embodiments of the present application easier to understand, and should not be regarded as limiting the scope of protection required by the present application.

[0142] 1、DMRS

[0143] The reference signal such as DMRS can be carried in the control channel (such as PDCCH) or data channel (such as PDSCH or PUSCH). Taking the case of carrying DMRS in the data channel as an example, DMRS can be used to estimate the equivalent channel of the data signal carried by the data channel, so as to be used for the detection and demodulation of data in the data channel. DMRS usually undergoes the same signal processing as data, such as precoding, so as to ensure that DMRS and data experience the same equivalent channel. Generally speaking, when DMRS is a reference signal carried by the uplink channel, it can be called uplink DMRS; when DMRS is a reference signal carried by the downlink channel, it can be called downlink DMRS.

[0144] Currently, according to different DMRS port division, the configuration type of DMRS can be divided into configuration type 1 (Type 1) and configuration type 2 (Type 2), and the number of orthogonal DMRS ports and time-frequency resource mapping rules supported by different configuration types are different. According to the number of symbols occupied by DMRS, DMRS can also be divided into single-symbol DMRS and double-symbol DMRS. Among them, DMRS Type 1 supports 4 DMRS ports in single-symbol and 8 DMRS ports in double-symbol; DMRS Type 2 supports 6 DMRS ports in single-symbol and 12 DMRS ports in double-symbol. It should be noted that the single-symbol and double-symbol mentioned in the present application are for the front DMRS symbol, and the understanding of the front DMRS symbol can be referred to the protocol 38.211.

[0145] In frequency domain, different DMRS ports are divided into different code division multiplexing groups, and DMRS ports in the same code division multiplexing group are expanded in time and frequency domain by using orthogonal cover code (OCC), and orthogonality of different DMRS ports can be ensured. The advantage of this is to improve the accuracy of channel estimation. Generally, one code division multiplexing group can include one or more scheduled / configured DMRS ports, and the DMRS ports use the same time-frequency resource but different OCC to send DMRS, that is, one code division multiplexing group includes one or more DMRS ports using the same time-frequency resource for transmission.

[0146] For example, refer to FIG. 2, which is a schematic diagram of an existing DMRS pattern. In FIG. 2, the columns represent the time domain, the rows represent the frequency domain, the number of columns represents the number of symbols, and the number of rows represents the number of REs in one RB. DMRS Type 1 is configured with 2 CDM groups (CDM group 0 and CDM group 1), and DMRS Type 2 is configured with 3 CDM groups (CDM group 0, CDM group 1, and CDM group 2). In FIG. 2, P0, P1, …, P11 represent the indexes of DMRS ports, and RE0, RE1, …, RE11 represent 12 REs included in one RB. Symbol 0 and symbol 1 are time domain symbols. The symbols (or time domain symbols) involved in the embodiments of the present application can be orthogonal frequency division multiplexing (OFDM) symbols, or can also be discrete fourier transform-spread-OFDM (DFT-s-OFDM) symbols, etc., which are not limited. For the convenience of understanding, the following mainly takes OFDM symbols as an example for understanding. In the present application, CDM group λ can be understood as a code division multiplexing group with index λ, for example, CDM group 0 can be understood as a code division multiplexing group with index 0, and the rest are similar. It should be understood that different CDM groups are frequency division multiplexed, and DMRS corresponding to DMRS ports included in the same CDM group are mapped on the same time-frequency resource. The DMRS sequences corresponding to the DMRS ports included in the same CDM group are distinguished by a mask sequence (such as an OCC sequence).

[0147] For DMRS Type 1 single symbol, it can support maximum 4 DMRS ports, as shown in (a) of FIG. 2, CDM group 0 = {P0 / P1}, CDM group 1 = {P2 / P3}, each DMRS port occupies 6 REs in one RB. Specifically, DMRS port 0 and DMRS port 1 contained in CDM group 0 occupy RE0, RE2, RE4, RE6, RE8, RE10 in one RB. DMRS port 2 and DMRS port 3 contained in CDM group 1 occupy RE1, RE3, RE5, RE7, RE9, RE11 in one RB.

[0148] For DMRS Type 1 double symbol, it can support maximum 8 DMRS ports, as shown in (b) of FIG. 2, CDM group 0 = {P0 / P1 / P4 / P5}, CDM group 1 = {P2 / P3 / P6 / P7}, each DMRS port occupies 6 REs in one RB. Specifically, DMRS port 0, DMRS port 1, DMRS port 4 and DMRS port 5 contained in CDM group 0 occupy RE0, RE2, RE4, RE6, RE8, RE10 in one RB. DMRS port 2, DMRS port 3, DMRS port 6 and DMRS port 7 contained in CDM group 1 occupy RE1, RE3, RE5, RE7, RE9, RE11 in one RB.

[0149] For DMRS Type 2 single symbol, it can support maximum 6 DMRS ports, as shown in (c) of FIG. 2, CDM group 0 = {P0 / P1}, CDM group 1 = {P2 / P3}, CDM group 2 = {P4 / P5}, each DMRS port occupies 4 REs in one RB. Specifically, DMRS port 0 and DMRS port 1 contained in CDM group 0 occupy RE0, RE1, RE6, RE7 in one RB. DMRS port 2 and DMRS port 3 contained in CDM group 1 occupy RE2, RE3, RE8, RE9 in one RB. DMRS port 4 and DMRS port 5 contained in CDM group 2 occupy RE4, RE5, RE10, RE11 in one RB.

[0150] For DMRS Type 2 two symbols, it can support a maximum of 12 DMRS ports, as shown in (d) of FIG. 2, CDM group 0 = {P0 / P1 / P6 / P7}, CDM group 1 = {P2 / P3 / P8 / P9}, CDM group 2 = {P4 / P5 / P10 / P11}, each DMRS port occupies 4 REs in one RB. Specifically, DMRS port 0, DMRS port 1, DMRS port 6 and DMRS port 7 contained in CDM group 0 occupy RE0, RE1, RE6, RE7 in one RB. DMRS port 2, DMRS port 3, DMRS port 8 and DMRS port 9 contained in CDM group 1 occupy RE2, RE3, RE8, RE9 in one RB. DMRS port 4, DMRS port 5, DMRS port 10 and DMRS port 11 contained in CDM group 2 occupy RE4, RE5, RE10, RE11 in one RB.

[0151] It should be noted that the present application mainly relates to the case where the configuration type of DMRS is Type 2.

[0152] 2、RE

[0153] RE is the minimum granularity physical layer resource, 1 subcarrier in frequency domain, and 1 orthogonal frequency division multiplexing (OFDM) symbol in time domain. The description of RE involved in the present application mainly refers to the frequency domain dimension, for example, the number of REs refers to the number of REs in different frequency domains under the same OFDM symbol, and for example, the REs occupied by the DMRS port can be understood as the subcarriers occupied by the DMRS port.

[0154] 3、Antenna Port and DMRS Port

[0155] In the present application, the antenna port can be understood as a kind of air interface environment based identifier of physical channel or physical signal. The same antenna port channel environment changes in the same way, and the receiver can perform channel estimation accordingly to demodulate the transmission signal. It should be noted that one antenna port can correspond to one reference signal, that is, the antenna port used for transmitting and / or receiving the reference signal can be referred to as the reference signal port, for example, taking the DMRS as the reference signal, the DMRS port can be understood as the antenna port used for transmitting and / or receiving the DMRS.

[0156] For example, for a DMRS port, the index of the DMRS port can be p (which can also be described as DMRS port p), and p can be an integer greater than or equal to 0. The index of the antenna port corresponding to the DMRS port p is 1000 + p (which can also be described as antenna port 1000 + p). That is, in the embodiments of the present application, the index p and the index 1000 + p can be understood as the index of the same DMRS port / antenna port.

[0157] 4. Configuration of DMRS resource parameters

[0158] For the indication of the DMRS resource parameters, it mainly includes ① indication of the configuration type (Type 1 or Type 2) of the DMRS of PUSCH / PDSCH, ② indication of the number of symbols occupied by the DMRS (single symbol or double symbol), and ③ indication of the port of the scheduled DMRS, etc.

[0159] ① For example, for the DMRS configuration of PUSCH, the following information element (IE) is shown, wherein the DMRS configuration type is configured by the high layer parameter "DMRS type (dmrs-Type)", and the configuration type of the DMRS shown in the following IE is Type 2.

[0160] ②The number of symbols occupied by DMRS is determined by the high-level parameter "max length" and the "antenna port(s)" field in the downlink control information (DCI). Specifically, when the value of maxLength is 1, it indicates that DMRS occupies a single symbol; when the value of maxLength is 2, it needs to be further combined with the "antenna port(s)" field in the DCI to determine whether DMRS occupies a single symbol or a double symbol. The "antenna port(s)" field indicates an index value, and based on the index value, the relevant parameters can be obtained by table lookup, as shown in Table 2. "Value" represents the index value indicated by the "antenna port(s)" field, and the value of the parameter "Number of front-load symbols" corresponding to each index value is used to indicate whether DMRS occupies a single symbol or a double symbol, where "Number of front-load symbols" represents the number of front-loaded DMRS symbols. For example, when the value of the parameter "Number of front-load symbols" is 1, it indicates that DMRS occupies a single symbol, and when the value of the parameter "Number of front-load symbols" is 2, it indicates that DMRS occupies a double symbol. The value of maxLength in the following IE example is 2.

[0161] It should be noted that currently when dmrs-Type is Type2, it is understood by default to be based on the configuration of 3 CDM groups of Type 2.

[0162] ③For the indication of the scheduled DMRS port, the "antenna port(s)" field in the DCI can be used to indicate the DMRS port and antenna port of the current scheduling time slot of the terminal. Specifically, the "antenna port(s)" field indicates an index value, and based on the index value, the relevant parameters can be obtained by table lookup. The length of the "antenna port(s)" field can be 4 bits, 5 bits or 6 bits, and the base station scheduling is based on different configurations to select different bit lengths. Both Table 1 and Table 2 below show the DMRS port mapping table corresponding to the configuration of 3 CDM groups of Type 2. Specifically, Table 1 corresponds to the case where maxLength = 1, and Table 2 corresponds to the case where maxLength = 2.

[0163] For example, the "Antenna port(s)" field in Table 1 can be used to indicate the value of the parameter "Value" in Table 1, which can be understood as an index value, based on which the value of the parameter "Number of DMRS CDM groups without data" and the value of the parameter "DMRS port(s)" can be determined, where the parameter "Number of DMRS CDM groups without data" represents the number of CDM groups without data transmission in the symbol where the current DMRS is located, and the parameter "DMRS port(s)" is the index of the scheduled DMRS port, and the index value of the corresponding antenna port is (1000+DMRS port). Optionally, one codeword (One codewords) is used when the number of scheduled DMRS ports is less than or equal to 4, and two codewords (Two codewords) are used when the number of scheduled DMRS ports is greater than 4.

[0164] For example, in the case of single codeword in Table 1, if the "Antenna port(s)" field of the DCI takes the value 1, it means that the number of CDM groups without data transmission in the symbol where the current DMRS is located is 1, the index of the scheduled DMRS port is 1, and the index of the corresponding antenna port is 1001; if the "Antenna port(s)" field of the DCI takes the value 7, it means that the number of CDM groups without data transmission in the symbol where the current DMRS is located is 2, the index of the scheduled DMRS port is 0 and 1, and the index of the corresponding antenna port is 1000 and 1001.

[0165] Table 1 DMRS port mapping: Antenna port(s) (1000+DMRS port), dmrs-Type = Type2, maxLength = 1

[0166] For example, in Table 2, the field of "Antenna port(s)" can be used to indicate the value of the parameter "Value" in Table 2, which can be understood as an index value, based on which the value of the parameter "Number of DMRS CDM groups without data", the value of the parameter "DMRS port(s)", and the value of the parameter "Number of front-load symbols" can be determined. For example, in Table 2, taking a single code word as an example, if the field of "Antenna port(s)" of the DCI takes the value of 1, it means that the number of CDM groups without data transmission in the symbol where the current DMRS is located is 1, the index of the scheduled DMRS port is 1, the index of the corresponding antenna port is 1001, and the number of front-loaded DMRS symbols is 1 (i.e., the number of symbols occupied by the DMRS is a single symbol). If the field of "Antenna port(s)" of the DCI takes the value of 24, it means that the number of CDM groups without data transmission in the symbol where the current DMRS is located is 3, the index of the scheduled DMRS port is 0, the index of the corresponding antenna port is 1000, and the number of front-loaded DMRS symbols is 2 (i.e., the number of symbols occupied by the DMRS is a double symbol).

[0167] Table 2 DMRS port mapping: Antenna port(s) (1000+DMRS port), dmrs-Type = Type 2, maxLength = 2

[0168] 5. Time-frequency resource mapping of DMRS port

[0169] For one DMRS port, the DMRS port can correspond to one or more DMRS signal symbols (also referred to as DMRS modulation symbols, or simply DMRS symbols). In order to perform channel estimation on different time-frequency resources, multiple DMRS symbols corresponding to the DMRS port can be transmitted in multiple time-frequency resources. In addition, in order to ensure the quality of channel estimation, different DMRS ports are usually orthogonal ports to avoid interference between different DMRS ports.

[0170] The multiple DMRS symbols corresponding to one DMRS port can correspond to one DMRS sequence, and one DMRS sequence includes multiple DMRS sequence elements. The DMRS sequence corresponding to one DMRS port can be mapped to the corresponding time-frequency resource by multiplying the corresponding mask sequence through the time-frequency resource mapping rule. For example, for the antenna port p j (p j= 1000 + p, where p is the index of the DMRS port), the (2n+k')th DMRS sequence element r(2n+k') in the corresponding DMRS sequence can be mapped to the RE with index The RE with index may correspond to the OFDM symbol with index I and the subcarrier with index k in a slot in the time domain. The time-frequency resource mapping rule can satisfy the following formula:

[0171] wherein, represents the DMRS sequence on the time-frequency resource (or described as, represents the antenna port p corresponding to the DMRS symbol) mapped to the RE with index j k; I represents the OFDM symbol index in the time-frequency resource; p j represents the index of the antenna port; μ represents the subcarrier spacing; represents the power scaling factor; w f (k') represents the frequency domain OCC (or described as, w f (k') is the frequency domain mask sequence element corresponding to the subcarrier with index k'); w t (l') represents the time domain OCC (or described as, w t (l') is the time domain mask sequence element corresponding to the OFDM symbol with index I'); r(2n+k') represents the pseudo-random sequence; represents the starting DMRS symbol index; I' represents the DMRS symbol relative index; v represents the number of scheduled antenna ports / DMRS ports; Δ represents the subcarrier offset factor.

[0172] Specifically, wherein P PDSCH represents the PDSCH power factor ratio (energy per resource element, EPRE), P DMRS represents the DMRS EPRE. The value of P may be obtained by looking up the table, for example, taking the configuration type of the DMRS as Type 2 (here Type 2 refers to the existing DMRS configuration type containing 3 code division multiplexing groups) as an example, as shown in Table 3, when the value of "Number of DMRS CDM groups without data" is 1, the value of P is 0 dB; when the value of "Number of DMRS CDM groups without data" is 2, the value of P is 3 dB. when the value of the "Number of DMRS CDM groups without data" is 3, when the value of the "Number of DMRS CDM groups without data" is 3,

[0173] Table 3 Ratio of PDSCH EPRE to DMRS EPRE dmrs-Type = Type2

[0174] For w f (k') and w t (l') when the configuration type of the DMRS is Type2, the values of w f (k'), w t (l') and Δ corresponding to the DMRS port p can be determined according to Table 4. Wherein, λ is the index of the CDM group to which the DMRS port p belongs, the time-frequency resources occupied by the DMRS ports in the same CDM group are the same, and the DMRS sequences corresponding to the DMRS ports in the same CDM group are distinguished by a mask sequence (such as an OCC sequence), so as to ensure the orthogonality of the DMRS ports in the CDM group and suppress the interference between the DMRSs transmitted on different DMRS ports. Alternatively, the aforementioned "time-frequency resources occupied by the DMRS port" can also be replaced by "time-frequency resources corresponding to the DMRS port" or "time-frequency resources mapped by the DMRS port" and the like.

[0175] Table 4 Parameter values corresponding to the DMRS port: dmrs-Type = Type2

[0176] It should be noted that in the scenario where the channel transmission delay spread is small, such as the UAM scenario, since there is often a direct path in the UAM scenario, the channel transmission delay spread is small, and if the existing Type 2 configuration is directly used for channel estimation, there will be a large resource overhead. Here, the so-called existing Type 2 configuration refers to a configuration containing 3 CDM groups, wherein each CDM group occupies 4 REs on each RB, as shown in the DMRS configuration Type 2 in FIG. 2.

[0177] Based on this, the present application proposes a communication method, which reduces the density of each CDM group of the DMRS in the frequency domain resource by expanding the number of CDM groups, thereby facilitating the reduction of the transmission resource overhead of the DMRS.

[0178] The communication method and the communication device provided in the present application are described in detail as follows.

[0179] Please refer to FIG. 3, which is a flowchart of the communication method provided in an embodiment of the present application. The method execution subject shown in FIG. 3 can be an access network device and a terminal. Alternatively, the method execution subject shown in FIG. 3 can be a chip in the access network device and a chip in the terminal. For the convenience of description, the present application mainly takes the access network device and the terminal as the execution subject for description. The steps or operations shown in FIG. 3 are only examples, and other operations or variations of the operations in FIG. 3 can also be executed by the embodiments of the present application. In addition, the steps in FIG. 3 can be executed in different order from that shown in FIG. 3, and it is possible that not all the operations in FIG. 3 are executed. Among them:

[0180] S301, the access network device sends first indication information to the terminal. Correspondingly, the terminal receives the first indication information from the access network device.

[0181] The first indication information is used to indicate the number Q of code division multiplexing groups supported by the configuration type 2 (i.e. Type 2) of DMRS, and Q is an integer greater than 3. Alternatively, it is described that the first indication information is used to indicate the configuration Type 2-Q CDM group of DMRS, or it is described that the first indication information is used to indicate the configuration of Q CDM groups based on Type 2. In the embodiments of the present application, Q is an integer greater than 3, for example, the value of Q can be 6, 12 or 24, etc., which is not limited in the present application.

[0182] Please refer to FIG. 4, which is a schematic diagram of the DMRS pattern of 6 CDM groups based on Type 2 provided in an embodiment of the present application. As shown in (a) of FIG. 4, it is the configuration of 6 CDM groups based on Type 2 in the case of single symbol, and as shown in (b) of FIG. 4, it is the configuration of 6 CDM groups based on Type 2 in the case of double symbol. Among them, the maximum number of DMRS ports supported is 12 in the case of single symbol, and the maximum number of DMRS ports supported is 24 in the case of double symbol. As can be seen from FIG. 4, when Q = 6, each CDM group occupies 2 REs on each RB.

[0183] Please refer to FIG. 5, which is a schematic diagram of a DMRS pattern of 12 CDM groups based on Type 2 provided by an embodiment of the present application. As shown in (a) of FIG. 5, it is a configuration of 12 CDM groups based on Type 2 in a single-symbol case, and as shown in (b) of FIG. 5, it is a configuration of 12 CDM groups based on Type 2 in a double-symbol case. Wherein, the maximum number of supported DMRS ports is 24 in the single-symbol case, and the maximum number of supported DMRS ports is 48 in the double-symbol case. As can be seen from FIG. 5, when Q=12, each CDM group occupies 2 REs on every 2 RBs, which is equivalent to each CDM group occupying 1 RE on every RB.

[0184] Please refer to FIG. 6, which is a schematic diagram of a DMRS pattern of 24 CDM groups based on Type 2 provided by an embodiment of the present application. As shown in (a) of FIG. 6, it is a configuration of 24 CDM groups based on Type 2 in a single-symbol case, and as shown in (b) of FIG. 6, it is a configuration of 24 CDM groups based on Type 2 in a double-symbol case. Wherein, the maximum number of supported DMRS ports is 48 in the single-symbol case, and the maximum number of supported DMRS ports is 96 in the double-symbol case. As can be seen from FIG. 6, when Q=24, each CDM group occupies 2 REs on every 4 RBs, which is equivalent to each CDM group occupying 0.5 RE on every RB.

[0185] In one implementation, the first indication information can be carried in high-layer signaling, such as an RRC message. In another implementation, the first indication information can also be carried in DCI, for example, a new field / bit can be added in the DCI to indicate the configuration of Q CDM groups based on Type 2. For the convenience of understanding, hereinafter, the first indication information carried in the RRC message will be mainly taken as an example for illustrative description.

[0186] In one design (I), for the existing high-layer parameter "dmrs-Type" in the RRC message, a new value of the "dmrs-Type" can be added, such as "Type2-QCDM group", to represent the configuration of Q CDM groups based on Type 2. That is, the high-layer parameter "dmrs-Type" can be reused to indicate the configuration of Q CDM groups based on Type 2.

[0187] For example, taking the DMRS configuration of PDSCH as an example, when Q=6, the RRC message configuration of PDSCH DMRS can be as follows.

[0188] In one design (ii), a new high-level parameter can also be added to the RRC message to indicate the configuration of Q CDM groups based on Type 2.

[0189] For example, taking the DMRS configuration of PDSCH as an example, assuming that the newly added higher-level parameter in the RRC message is the number of CDM groups "cdm-group number", when Q=6, the corresponding RRC message configuration of PDSCH DMRS can be as follows.

[0190] For example, a new high-level parameter added to the RRC message could be a flag. Then: if the flag is not present in the RRC message, it indicates a configuration based on three CDM groups of Type 2 (i.e., the existing configuration); if the flag is present in the RRC message, it indicates a configuration based on Q CDM groups of Type 2. Alternatively, if the flag's value is 0, it indicates a configuration based on three CDM groups of Type 2 (i.e., the existing configuration); if the flag's value is 1, it indicates a configuration based on Q CDM groups of Type 2.

[0191] Optionally, the indication of the number of symbols occupied by DMRS (i.e., single or double symbols) can be determined by the high-level parameter "maxLength" and the "Antenna port(s)" field in DCI, which will not be elaborated here.

[0192] S302. The access network device sends a second instruction message to the terminal. Correspondingly, the terminal receives the second instruction message from the access network device.

[0193] The second indication information is used to indicate the number of first code division multiplexing groups and the index of the first DMRS port, wherein the number of first code division multiplexing groups is the number of code division multiplexing groups that do not support DMRS and data multiplexing (or referred to as "Number of DMRS CDM groups without data"), and the index of the first DMRS port is the index of the scheduled DMRS port (or described as the index of the DMRS port used, or the index of the configured DMRS port, or the index of the occupied DMRS port, or the index of the allocated DMRS port).

[0194] The number of the first code division multiplexer group mentioned above is an integer greater than or equal to 4 and less than or equal to Q, or the number of the first code division multiplexer group is an integer greater than or equal to 1 and less than or equal to Q.

[0195] The number of the first DMRS port indexes is at least one, and the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 4Q-1. Specifically, in the case of the maximum length of the DMRS being 1 (i.e., maxLength=1), the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 2Q-1; in the case of the maximum length of the DMRS being 2 (i.e., maxLength=2), the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 4Q-1.

[0196] In a possible implementation (1), the second indication information can be carried in the DCI, for example, the second indication information can be an antenna port field (i.e., an "Antenna port(s)" field), where the "Antenna port(s)" field indicates an index value (for the sake of distinction, hereinafter referred to as a first index value), and the first index value corresponds to the first number of code division multiplexing groups and the first DMRS port index, or the first index value has a mapping relationship with the first number of code division multiplexing groups and the first DMRS port index. That is, the "Antenna port(s)" field indicating the index value in the existing DCI can be reused, and the reserved bits in the existing DMRS port mapping table are used to indicate the "Number of DMRS CDM groups without data" and the scheduled DMRS port.

[0197] For example, in the case of Q=6, the first number of code division multiplexing groups can be an integer greater than or equal to 1 and less than or equal to 6. In the case of the maximum length of the DMRS being 1, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 11. In the case of the maximum length of the DMRS being 2, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 23. For example, Table 5 shows the DMRS port mapping table when Q=6 and maxLength=1, and the black and bold part is the mapping relationship newly added by the embodiment of the application compared with Table 1.

[0198] Table 5 DMRS port mapping: Antenna port(s) (1000+DMRS port), dmrs-Type=Type2-6 CDM group, maxLength=1

[0199] For example, Table 6 shows the DMRS port mapping table when Q=6 and maxLength=2, and the black and bold part is the mapping relationship newly added by the embodiment of the application compared with Table 2.

[0200] Table 6 DMRS port mapping: Antenna port(s) (1000 + DMRS port), dmrs-Type = Type2-6 CDM group, maxLength = 2

[0201] Exemplarily, taking Q=12 as an example, the first number of code division multiplexing groups can be an integer greater than or equal to 1 and less than or equal to 12. In the case of the maximum length of DMRS being 1, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 23. In the case of the maximum length of DMRS being 2, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 47. Exemplarily, Table 7 shows the DMRS port mapping table when Q=12 and maxLength=1, and the black and bold part is the mapping relationship newly added by the embodiment of the application compared with Table 1.

[0202] Table 7 DMRS port mapping: Antenna port(s) (1000 + DMRS port), dmrs-Type = Type2-6 CDM group, maxLength = 2

[0203] Exemplarily, Table 8 shows the DMRS port mapping table when Q=12 and maxLength=2, and the black and bold part is the mapping relationship newly added by the embodiment of the application compared with Table 2.

[0204] Table 8 DMRS port mapping: Antenna port(s) (1000 + DMRS port), dmrs-Type = Type2-6 CDM group, maxLength = 2

[0205] Exemplarily, taking Q=24 as an example, the first number of code division multiplexing groups can be an integer greater than or equal to 1 and less than or equal to 24. In the case of the maximum length of DMRS being 1, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 47. In the case of the maximum length of DMRS being 2, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 95.

[0206] It can be understood that in the implementation scheme (1), it is usually necessary to first query the corresponding first code division multiplexing group quantity and first DMRS port index from the DMRS port mapping table based on the first index value indicated by the second indication information, and then determine the CDM group to which the first DMRS port index belongs as the scheduled CDM group (or described as the used CDM group, or the configured CDM group, or the occupied CDM group, or the allocated CDM group). Wherein, the scheduled CDM group is contained in the Q CDM groups, and the index value of the scheduled CDM group is an integer greater than or equal to 0 and less than or equal to Q-1.

[0207] In a possible implementation scheme (2), in order to make the indication of the first code division multiplexing group quantity and the first DMRS port index more flexible, a new field / bit can be added in the DCI to implement more complete antenna port indication. In the implementation scheme (2), there are mainly the following three indications: (2-1) indication of the scheduled CDM group; (2-2) indication of the scheduled DMRS port in the scheduled CDM group; (2-3) indication of the quantity of code division multiplexing groups (i.e. the first code division multiplexing group quantity) that do not support DMRS and data multiplexing.

[0208] (2-1) For the indication of the scheduled CDM group, a new field / bit can be added in the DCI to indicate the use of the CDM group.

[0209] For example, the scheduled CDM groups can be indicated by a bitmap, where one bit in the bitmap corresponds to one CDM group. For example, when Q=6, the length of the corresponding bitmap is 6 bits. When the value of the bitmap is 100000, it indicates that CDM group 0 is occupied (or the scheduled CDM group is CDM group 0); when the value of the bitmap is 010000, it indicates that CDM group 1 is occupied; when the value of the bitmap is 001000, it indicates that CDM group 2 is occupied; when the value of the bitmap is 000100, it indicates that CDM group 3 is occupied; when the value of the bitmap is 000010, it indicates that CDM group 4 is occupied; when the value of the bitmap is 000001, it indicates that CDM group 5 is occupied; when the value of the bitmap is 000011, it indicates that CDM groups 4 and 5 are occupied; and when the value of the bitmap is 100001, it indicates that CDM groups 0 and 5 are occupied. For example, when Q=12, the length of the corresponding bitmap is 12 bits. When the value of the bitmap is 010000000000, it indicates that CDM group 1 is occupied. For example, when Q=24, the length of the corresponding bitmap is 24 bits. When the value of the bitmap is 010000000000000000000000, it indicates that CDM group 1 is occupied. It should be noted that the correspondence between each bit in the bitmap and the CDM group is not limited in this application.

[0210] For example, the scheduled CDM groups can be indicated by a bitmap, where one bit in the bitmap corresponds to one CDM group. For example, when Q=6, the length of the corresponding bitmap is 6 bits. When the value of the bitmap is 100000, it indicates that CDM group 0 is occupied (or the scheduled CDM group is CDM group 0); when the value of the bitmap is 010000, it indicates that CDM group 1 is occupied; when the value of the bitmap is 001000, it indicates that CDM group 2 is occupied; when the value of the bitmap is 000100, it indicates that CDM group 3 is occupied; when the value of the bitmap is 000010, it indicates that CDM group 4 is occupied; when the value of the bitmap is 000001, it indicates that CDM group 5 is occupied; when the value of the bitmap is 000011, it indicates that CDM groups 4 and 5 are occupied; and when the value of the bitmap is 100001, it indicates that CDM groups 0 and 5 are occupied. For example, when Q=12, the length of the corresponding bitmap is 12 bits. When the value of the bitmap is 010000000000, it indicates that CDM group 1 is occupied. For example, when Q=24, the length of the corresponding bitmap is 24 bits. When the value of the bitmap is 010000000000000000000000, it indicates that CDM group 1 is occupied. It should be noted that the correspondence between each bit in the bitmap and the CDM group is not limited in this application.

[0211] It should be noted that the number of added bits in the DCI is not limited in this application, and the way of indicating the use of CDM groups by the added bits is also not limited.

[0212] (2-2) For the indication of the scheduled DMRS port in the scheduled CDM group, a new bit / field can be added in the DCI to indicate the usage / scheduling / occupation of the DMRS port in the scheduled CDM group, or the “Antenna port(s)” field can be modified to indicate the usage / scheduling / occupation of the DMRS port in the scheduled CDM group.

[0213] For example, in the case of a single symbol, when indicating the specific DMRS port used by each scheduled CDM group, when the number of scheduled CDM groups is 1, 2 bits can be used to indicate the scheduled DMRS port; when the number of scheduled CDM groups is 2, 4 bits can be used to indicate the scheduled DMRS port; when the number of scheduled CDM groups is 3, 6 bits can be used to indicate the scheduled DMRS port; when the number of scheduled CDM groups is 4, 8 bits can be used to indicate the scheduled DMRS port, and so on, where each 2 bits is used to indicate the scheduled DMRS port in one scheduled CDM group. Optionally, the 2 bits can be arranged in ascending order (or descending order, or other order) of the index of the scheduled CDM group. For example, taking CDM group 0 and CDM group 1 as an example, b0b1b2b3 in b0b1b2b3 corresponds to CDM group 0, and b2b3 corresponds to CDM group 1.

[0214] For example, in the case of a single symbol, when indicating the specific DMRS port used by each scheduled CDM group, when the number of scheduled CDM groups is 1, 2 bits can be used to indicate the scheduled DMRS port; when the number of scheduled CDM groups is 2, 4 bits can be used to indicate the scheduled DMRS port; when the number of scheduled CDM groups is 3, 6 bits can be used to indicate the scheduled DMRS port; when the number of scheduled CDM groups is 4, 8 bits can be used to indicate the scheduled DMRS port, and so on, where each 2 bits is used to indicate the scheduled DMRS port in one scheduled CDM group. Optionally, the 2 bits can be arranged in ascending order (or descending order, or other order) of the index of the scheduled CDM group. For example, taking CDM group 0 and CDM group 1 as an example, b0b1b2b3 in b0b1b2b3 corresponds to CDM group 0, and b2b3 corresponds to CDM group 1.

[0215] For convenience of description, in the following, the indication of the DMRS port of the scheduled CDM group is mainly taken as an example for description in a single symbol. For example, as shown in Table 9 below, the indication of the DMRS port corresponding to the scheduled CDM group being CDM group 0 in a single symbol is shown. Specifically, when the value of Value is 0, it indicates that the DMRS port 0 is used, that is, the antenna port 1000 is used; when the value of Value is 1, it indicates that the DMRS port 1 is used, that is, the antenna port 1001 is used; and when the value of Value is 2, it indicates that the DMRS ports 0 and 1 are used, that is, the antenna ports 1000 and 1001 are used.

[0216] Table 9 CDM group 0: Antenna port(s) (1000+DMRS port), dmrs-Type = Type 2-6 / 12 / 24 CDM group, maxLength = 1

[0217] For another example, as shown in Table 10 below, the indication of the DMRS port corresponding to the scheduled CDM group being CDM group 1 in a single symbol is shown. Specifically, when the value of Value is 0, it indicates that the DMRS port 2 is used, that is, the antenna port 1002 is used; when the value of Value is 1, it indicates that the DMRS port 3 is used, that is, the antenna port 1003 is used; and when the value of Value is 2, it indicates that the DMRS ports 2 and 3 are used, that is, the antenna ports 1002 and 1003 are used.

[0218] Table 10 CDM group 1: Antenna port(s) (1000+DMRS port), dmrs-Type = Type 2-6 / 12 / 24 CDM group, maxLength = 1

[0219] (2-3) For the indication of the number of code division multiplexing groups without supporting DMRS and data multiplexing (i.e., "Number of DMRS CDM groups without data"), a new field / bit in the DCI can be used for the indication. Generally, the new field / bit in the DCI can directly indicate the specific value of the number of code division multiplexing groups without supporting DMRS and data multiplexing, or the new field / bit in the DCI can indirectly indicate the specific value of the number of code division multiplexing groups without supporting DMRS and data multiplexing, for example, it can indicate an index value, wherein one index value corresponds to one specific value of the number of code division multiplexing groups without supporting DMRS and data multiplexing. Understandably, compared with the direct indication mode, the indirect indication mode is more conducive to saving bit overhead.

[0220] For example, when Q=6, the number of new bits in the DCI for indicating "Number of DMRS CDM groups without data" can be 4 bits, and the 4 bits are used to carry an index value, as shown in Table 11 below. When the index value is 0, it means that "Number of DMRS CDM groups without data" is 1; when the index value is 1, it means that "Number of DMRS CDM groups without data" is 2; when the index value is 2, it means that "Number of DMRS CDM groups without data" is 3; when the index value is 3, it means that "Number of DMRS CDM groups without data" is 4; when the index value is 4, it means that "Number of DMRS CDM groups without data" is 5; when the index value is 5, it means that "Number of DMRS CDM groups without data" is 6.

[0221] Table 11 "Number of DMRS CDM groups without data" indication mapping table: dmrs-Type=Type2-6CDM group

[0222] For example, when Q=12, the number of newly added bits in the DCI for indicating the "Number of DMRS CDM groups without data" can be 4 bits, and the 4 bits are used to carry the index value, as shown in Table 12 below. When the index value is 0, it means that the "Number of DMRS CDM groups without data" is 1; when the index value is 1, it means that the "Number of DMRS CDM groups without data" is 2; when the index value is 2, it means that the "Number of DMRS CDM groups without data" is 3; when the index value is 3, it means that the "Number of DMRS CDM groups without data" is 4; when the index value is 4, it means that the "Number of DMRS CDM groups without data" is 5; when the index value is 5, it means that the "Number of DMRS CDM groups without data" is 6; when the index value is 6, it means that the "Number of DMRS CDM groups without data" is 7; when the index value is 7, it means that the "Number of DMRS CDM groups without data" is 8; when the index value is 8, it means that the "Number of DMRS CDM groups without data" is 9; when the index value is 9, it means that the "Number of DMRS CDM groups without data" is 10; when the index value is 10, it means that the "Number of DMRS CDM groups without data" is 11; when the index value is 11, it means that the "Number of DMRS CDM groups without data" is 12.

[0223] Table 12 Mapping table of "Number of DMRS CDM groups without data" indication: dmrs-Type = Type2-12 CDM group

[0224] For example, when Q = 24, the number of new bits in the DCI used to indicate "Number of DMRS CDM groups without data" can be 5 bits. These 5 bits are used to carry the index value, as shown in Table 13 below. When the index value is 0, it means "Number of DMRS CDM groups without data" is 1; when the index value is 1, it means "Number of DMRS CDM groups without data" is 2; when the index value is 2, it means "Number of DMRS CDM groups without data" is 3; and so on. When the index value is 23, it means "Number of DMRS CDM groups without data" is 24.

[0225] Table 13, “Number of DMRS CDM groups without data”, indicates the mapping table: dmrs-Type = Type2-24CDM group

[0226] S303. The terminal sends DMRS according to the first instruction information and the second instruction information. Correspondingly, the access network equipment receives the DMRS from the terminal.

[0227] Understandably, for uplink DMRS, the terminal can send DMRS according to the first indication information and the second indication information, and correspondingly, the access network device receives the DMRS from the terminal. For downlink DMRS, the access network device sends DMRS, and correspondingly, the terminal can receive the DMRS from the access network device according to the first indication information and the second indication information.

[0228] Specifically, the terminal receiving (or transmitting) the DMRS based on the first and second indication information can be understood as follows: the terminal determines the time-frequency resource and DMRS sequence corresponding to the DMRS based on the first and second indication information, and then can receive (or transmit) the DMRS sequence on that time-frequency resource. Correspondingly, for the access network equipment, the access network equipment can also first determine the time-frequency resource and DMRS sequence corresponding to the DMRS, and then can transmit (or receive) the DMRS sequence on that time-frequency resource. Understandably, for the receiver of the DMRS sequence, it can perform channel estimation based on the received DMRS sequence for subsequent detection and demodulation of data in the data channel.

[0229] Generally speaking, the DMRS sequence and time-frequency resources mentioned above satisfy the following conditions:

[0230] wherein, denotes a DMRS sequence on a time-frequency resource; k denotes a subcarrier index in the time-frequency resource; l denotes an orthogonal frequency-division multiplexing, OFDM, symbol index in the time-frequency resource; pj denotes an index of an antenna port; μ denotes a subcarrier spacing; denotes a power scaling factor, relates to a first number of code-division multiplexing, CDM, groups; w f (k′) denotes a frequency-domain orthogonal cover code, OCC; w t (l′) denotes a time-domain OCC; r(2n+k′) denotes a pseudo-random sequence; denotes a starting DMRS symbol index; l′ denotes a DMRS symbol relative index; v denotes a first number of DMRS port indexes; △ denotes a subcarrier offset factor; Q is a number of CDM groups supported by a configuration type 2 of DMRS.

[0231] For example, when Q = 6, k = 12n+k′+△. For another example, when Q = 12, k = 24n+k′+△. For yet another example, when Q = 24, k = 48n+k′+△.

[0232] Optionally, for the above , it can satisfy:

[0233] wherein, P denotes a first number of CDM groups (i.e., “Number of DMRS CDM groups without data”).

[0234] For example, when Q = 6, the value of k can be obtained by referring to Table 14, wherein the black and bold part in Table 14 is a mapping relationship newly added by the embodiment of the present application, which is different from the existing Table 3.

[0235] Table 14 Ratio of PDSCH EPRE to DMRS EPRE Type2-6 CDM group

[0236] For example, when Q = 12, the value of k can be obtained by referring to Table 15, wherein the black and bold part in Table 15 is a mapping relationship newly added by the embodiment of the present application, which is different from the existing Table 3.

[0237] Table 15 Ratio of PDSCH EPRE to DMRS EPRE Type2-12 CDM group

[0238] Exemplarily, when Q=24, The values of Δ, w

[0239] Table 16 PDSCH EPRE to DMRS EPRE ratio Type2-24 CDM group

[0240] For the above formula, the values of Δ, w f (k') and w t (l') are needed. In order to adapt to the DMRS pattern proposed in the present application, a new mapping table of parameter values corresponding to the DMRS port is proposed. Specifically, the values of Δ, w f (k') and w t (l') can be determined by looking up the table according to the first DMRS port index. Wherein Δ is an integer greater than or equal to 0 and less than or equal to 2*(Q-1), and different DMRS ports in the code division multiplexing group to which the first DMRS port index belongs are orthogonal.

[0241] Exemplarily, as shown in the following table 17, when Q=6, the parameter values corresponding to the DMRS port are shown, wherein p represents the index of the DMRS port, λ represents the index of the CDM group, Δ represents the subcarrier offset factor, [w f (0) w f (1)] represents the frequency domain OCC, and [w t (0) w t (1)] represents the time domain OCC. The frequency domain OCC and the time domain OCC are used to ensure that different DMRS ports in the same code division multiplexing group are orthogonal. The black bold part is the mapping relationship of the present application embodiment distinguished from table 4.

[0242] Table 17 Parameter values corresponding to the DMRS port: Type2-6 CDM group

[0243] Exemplarily, as shown in the following table 18, when Q=12, the parameter values corresponding to the DMRS port are shown, wherein p represents the index of the DMRS port, λ represents the index of the CDM group, Δ represents the subcarrier offset factor, [w f (0) w f (1)] represents the frequency domain OCC, and [w t (0) w t(1)] represents the time-domain OCC. The frequency-domain OCC and time-domain OCC are used to ensure that different DMRS ports within the same code division multiplexing group are orthogonal. The bolded part is the mapping relationship in the embodiment of this application that differs from that in Table 4.

[0244] Table 18 Parameter values ​​corresponding to DMRS ports: Type2-12CDM group

[0245] For example, Table 19 below shows the parameter values ​​for the DMRS port when Q=24, where p represents the index of the DMRS port, λ represents the index of the CDM group, Δ represents the subcarrier offset factor, [w f (0) w f (1)] represents the frequency domain OCC, [w t (0) w t (1)] represents the time-domain OCC. The frequency-domain OCC and time-domain OCC are used to ensure that different DMRS ports within the same code division multiplexing group are orthogonal.

[0246] Table 19 shows the parameter values ​​for the DMRS port: Type 2-24CDM group

[0247] In this embodiment, a sparse DMRS pattern with Q (Q>3) CDM groups is designed based on DMRS Type 2, thereby expanding the number of CDM groups and reducing the density of each CDM group in the frequency domain, which in turn helps to reduce the transmission resource overhead of DMRS.

[0248] Please refer to Figure 7, which is another flowchart illustrating the communication method provided in an embodiment of this application. The method execution entities shown in Figure 7 can be access network devices and terminals. Alternatively, the method execution entities shown in Figure 7 can also be chips in the access network device and chips in the terminal. For ease of description, this application mainly uses access network devices and terminals as the execution entities. The steps or operations shown in Figure 7 are merely examples; other operations or variations of the various operations in Figure 7 can also be performed in the embodiments of this application. Furthermore, the steps in Figure 7 can be performed in a different order than that presented in Figure 7, and it is possible that not all operations in Figure 7 need to be performed. Wherein:

[0249] S701. The access network device sends a request message to the terminal. Correspondingly, the terminal receives the request message from the access network device.

[0250] The request information is used for requesting the terminal to report the capability information. Exemplarily, the request information can be carried in an RRC message or DCI.

[0251] Step S701 is an optional step.

[0252] S702. The terminal sends the capability information to the access network device. Correspondingly, the access network device receives the capability information from the terminal.

[0253] The capability information indicates that the terminal supports Q code division multiplexing groups of configuration type 2 based on DMRS, where Q is an integer greater than 3. Exemplarily, the capability information can be carried in an RRC message or UCI.

[0254] In one possible implementation, the terminal can report its capability information to the access network device based on the request information in step S701. In another possible implementation, the terminal can also actively report its capability information to the access network device.

[0255] S703. The access network device sends first indication information to the terminal. Correspondingly, the terminal receives the first indication information from the access network device.

[0256] S704. The access network device sends second indication information to the terminal. Correspondingly, the terminal receives the second indication information from the access network device.

[0257] S705. The terminal sends DMRS according to the first indication information and the second indication information. Correspondingly, the access network device receives the DMRS from the terminal.

[0258] The understanding of steps S703-S705 can refer to the description of steps S301-S303 in the foregoing corresponding embodiment of FIG. 3, and will not be repeated here.

[0259] In the embodiments of the present application, the terminal reports its capability of supporting Q (Q>3) CDM groups of DMRS based on Type 2, so that the access network device can configure the pattern of DMRS based on Type 2 of Q CDM groups for the terminal based on the capability supported by the terminal, thereby expanding the number of CDM groups, reducing the density of each CDM group of DMRS in the frequency domain resource, and further facilitating to reduce the transmission resource overhead of DMRS.

[0260] The communication apparatus provided by the present application will be described in detail below with reference to FIGS. 8-9.

[0261] It should be noted that the communication apparatus includes hardware structures and / or software modules corresponding to the functions in the above embodiments in order to realize the functions. Those skilled in the art should easily understand that, in combination with the units and method steps of the examples described in the embodiments disclosed in the present application, the present application can be realized in the form of hardware or a combination of hardware and computer software. Whether a certain function is realized in the form of hardware or computer software driving hardware depends on the specific application scenarios and design constraints of the technical solutions.

[0262] FIG. 8 and FIG. 9 are structural schematic diagrams of possible communication apparatuses provided by the embodiments of the present application. These communication apparatuses can be used to realize the functions of the terminal or the access network device (for example, the base station) in the above method embodiments, and thus can also realize the beneficial effects possessed by the above method embodiments. In the embodiments of the present application, the communication apparatus can be one of the terminals 120a-120j as shown in FIG. 1, or can also be the RAN node 110a or 110b as shown in FIG. 1. Alternatively, it can also be a module (such as a chip) applied to the terminal or the access network device.

[0263] As shown in FIG. 8, the communication apparatus 800 includes a processing unit 810 and a transceiver unit 820. The communication apparatus 800 is used to realize the functions of the terminal or the access network device in the method embodiments shown in FIG. 3 or FIG. 7.

[0264] When the communication apparatus 800 is used to realize the functions of the terminal in the method embodiments shown in FIG. 3 or FIG. 7:

[0265] The transceiver unit 820 is configured to receive first indication information, where the first indication information is used to indicate a number Q of code division multiplexing groups supported by a configuration type 2 of a demodulation reference signal (DMRS), and the Q is an integer greater than 3.

[0266] The transceiver unit 820 is configured to receive second indication information, where the second indication information is used to indicate a first code division multiplexing group number and a first DMRS port index, the first code division multiplexing group number is a number of code division multiplexing groups that do not support multiplexing of DMRS and data, the first DMRS port index is an index of a scheduled DMRS port, the first code division multiplexing group number is an integer greater than or equal to 4 and less than or equal to Q, the number of the first DMRS port index is at least one, and the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 4Q-1.

[0267] The transceiver unit 820 is configured to receive or send the DMRS according to the first indication information and the second indication information.

[0268] In a possible implementation, the second indication information is carried in a downlink control information (DCI), and the second indication information is an antenna port field, the antenna port field indicating a first index value, the first index value corresponding to the first number of code division multiplexing (CDM) groups and the first DMRS port index.

[0269] In a possible implementation, in a case where the maximum length of the DMRS is 1, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 2Q-1.

[0270] In a possible implementation, in a case where the maximum length of the DMRS is 2, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 4Q-1.

[0271] In a possible implementation, the CDM group to which the first DMRS port index belongs is a scheduled CDM group, the scheduled CDM group being included in the Q CDM groups, and the value of an index of the scheduled CDM group is an integer greater than or equal to 0 and less than or equal to Q-1.

[0272] In a possible implementation, the communication apparatus further includes a processing unit 810, and wherein:

[0273] The processing unit 810 is configured to determine, according to the first indication information and the second indication information, the time-frequency resource and the DMRS sequence corresponding to the DMRS.

[0274] The transceiver unit 820 is configured to receive or send the DMRS sequence on the time-frequency resource.

[0275] In a possible implementation, the DMRS sequence on the time-frequency resource and the time-frequency resource respectively satisfy:

[0276] wherein the represents the DMRS sequence on the time-frequency resource;

[0277] The k represents a subcarrier index in the time-frequency resource.

[0278] The l represents an orthogonal frequency division multiplexing (OFDM) symbol index in the time-frequency resource.

[0279] The p j represents an index of an antenna port.

[0280] The μ represents a subcarrier spacing.

[0281] The represents a power scaling factor, and the The first number of code division multiplexing groups is related to;

[0282] The w f (k') represents a frequency domain orthogonal cover code (OCC);

[0283] The w t (l') represents a time domain OCC;

[0284] The r(2n+k') represents a pseudo-random sequence;

[0285] The represents a starting DMRS symbol index;

[0286] The l' represents a DMRS symbol relative index;

[0287] The v represents a number of the first DMRS port indexes;

[0288] The delta represents a subcarrier offset factor;

[0289] The Q is a number of code division multiplexing groups supported by a configuration type 2 of DMRS.

[0290] In a possible implementation, the first number of code division multiplexing groups is related to is satisfied.

[0291] The P represents the first number of code division multiplexing groups.

[0292] In a possible implementation, the first DMRS port index corresponds to the delta, the w f (k') and the w t (l'); the delta is an integer greater than or equal to 0 and less than or equal to 2*(Q-1), and different DMRS ports in a code division multiplexing group to which the first DMRS port index belongs are orthogonal.

[0293] In a possible implementation, the transceiver 820 is configured to send capability information, and the capability information indicates that the terminal supports Q code division multiplexing groups of a configuration type 2 based on DMRS.

[0294] In a possible implementation, the capability information is carried in an RRC message or UCI.

[0295] In a possible implementation, the transceiver 820 is configured to receive request information, and the request information is used to request the terminal to report the capability information.

[0296] In a possible implementation, the request information is carried in an RRC message or DCI.

[0297] In a possible implementation, the first indication information is carried in an RRC message.

[0298] When the communication apparatus 800 is configured to implement the functions of the access network device in the method embodiments shown in FIG. 3 or FIG. 7:

[0299] The transceiver is configured to send first indication information, the first indication information being used to indicate a number Q of code division multiplexing groups supported by a configuration type 2 of demodulation reference signal (DMRS), the Q being an integer greater than 3;

[0300] The transceiver is configured to send second indication information, the second indication information being used to indicate a first number of code division multiplexing groups and a first DMRS port index, wherein the first number of code division multiplexing groups is a number of code division multiplexing groups that do not support multiplexing of DMRS and data, the first DMRS port index is an index of a scheduled DMRS port, the first number of code division multiplexing groups is an integer greater than or equal to 4 and less than or equal to Q, the number of the first DMRS port index is at least one, and the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 4Q-1.

[0301] The first indication information and the second indication information are used to receive or send DMRS.

[0302] In a possible implementation, the second indication information is carried in a downlink control information (DCI), and the second indication information is an antenna port field, the antenna port field indicating a first index value, the first index value corresponding to the first number of code division multiplexing groups and the first DMRS port index.

[0303] In a possible implementation, in a case where the maximum length of the DMRS is 1, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 2Q-1.

[0304] In a possible implementation, in a case where the maximum length of the DMRS is 2, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 4Q-1.

[0305] In a possible implementation, a code division multiplexing group to which the first DMRS port index belongs is a scheduled code division multiplexing group, the scheduled code division multiplexing group being included in the Q code division multiplexing groups, and the value of an index of the scheduled code division multiplexing group is an integer greater than or equal to 0 and less than or equal to Q-1.

[0306] In a possible implementation, the transceiver is configured to receive capability information, the capability information indicating that a terminal supports Q code division multiplexing groups based on the configuration type 2 of DMRS.

[0307] In a possible implementation, the capability information is carried in an RRC message or UCI.

[0308] In a possible implementation, the transceiver is configured to send request information, where the request information is used to request the terminal to report the capability information.

[0309] In a possible implementation, the request information is carried in an RRC message or DCI.

[0310] In a possible implementation, the first indication information is carried in an RRC message.

[0311] For more details of the processing unit 810 and the transceiver 820, refer to the related description in the method embodiments shown in FIG. 3 or FIG. 7.

[0312] As shown in FIG. 9, the communication apparatus 900 includes a processor 910, and optionally further includes an interface circuit 920. The processor 910 and the interface circuit 920 are coupled to each other. It can be understood that the interface circuit 920 can be a transceiver or an input / output interface. Optionally, the communication apparatus 900 can further include a memory 930, used to store instructions executed by the processor 910 or to store input data required by the processor 910 to execute instructions or to store data generated after the processor 910 executes instructions.

[0313] When the communication apparatus 900 is used to implement the method shown in FIG. 3 or FIG. 7, the processor 910 is configured to implement the functions of the processing unit 810, and the interface circuit 920 is configured to implement the functions of the transceiver 820.

[0314] When the above communication apparatus is a terminal chip, the terminal chip implements the functions of the terminal in the above method embodiments. The terminal chip receives information sent by the access network device to the terminal through other modules (such as a radio frequency module or an antenna) in the terminal; or the terminal chip sends information to other modules (such as a radio frequency module or an antenna) in the terminal, where the information is sent by the terminal to the access network device.

[0315] When the communication device is a module applied to an access network device, the access network device module implements the functions of the access network device in the method embodiments. The access network device module receives information from other modules (such as a radio frequency module or an antenna) in the access network device, and the information is sent by the terminal to the access network device. Alternatively, the access network device module sends information to other modules (such as a radio frequency module or an antenna) in the access network device, and the information is sent by the access network device to the terminal. The access network device module herein can be a baseband chip of the access network device, or a CU, a DU or other modules, or a device under the open radio access network (O-RAN) architecture, such as an open CU, an open DU, etc.

[0316] It can be understood that the processor in the embodiments of the present application can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. The general-purpose processor can be a microprocessor or any conventional processor.

[0317] The method steps in the embodiments of the present application can be implemented in hardware or in software instructions executable by a processor. The software instructions can be composed of corresponding software modules, which can be stored in a random access memory, a flash memory, a read-only memory, a programmable read-only memory, an erasable programmable read-only memory, an electrically erasable programmable read-only memory, a register, a hard disk, a mobile hard disk, a CD-ROM or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor, so that the processor can read information from the storage medium and write information to the storage medium. The storage medium can also be an integral part of the processor. The processor and the storage medium can be located in an ASIC. In addition, the ASIC can be located in an access network device or a terminal. The processor and the storage medium can also exist as discrete components in the access network device or the terminal.

[0318] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer programs or instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are performed. The computer can be a general purpose computer, a special purpose computer, a computer network, a network device, a user equipment or other programmable apparatus. The computer programs or instructions can be stored in a computer readable storage medium or transferred from one computer readable storage medium to another computer readable storage medium, for example, the computer programs or instructions can be transferred from one website site, computer, server or data center to another website site, computer, server or data center through wired or wireless manner. The computer readable storage medium can be any available medium accessible by a computer or a data storage device such as a server, data center and the like integrated with one or more available media. The available media can be a magnetic medium, such as a floppy disk, a hard disk, a magnetic tape; an optical medium, such as a digital video disc; and a semiconductor medium, such as a solid state disk. The computer readable storage medium can be a volatile or non-volatile storage medium, or can include both volatile and non-volatile storage media.

[0319] In various embodiments of the present application, the terms and / or descriptions of different embodiments are consistent and can be referred to each other if there is no special description and logical conflict, and the technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0320] It can be understood that various numerical numbers involved in the embodiments of the present application are only for convenient differentiation, and are not used to limit the scope of the embodiments of the present application. The size of the serial number of the above processes does not mean the execution order, and the execution order of the processes should be determined according to its function and inherent logic.

Claims

1. A communication method, characterized in that, include: Receive first indication information, the first indication information being used to indicate the number Q of code division multiplexing groups supported by configuration type 2 of demodulation reference signal DMRS, wherein Q is an integer greater than 3; Receive second indication information, the second indication information is used to indicate the number of first code division multiplexing groups and the first DMRS port index, wherein the number of first code division multiplexing groups is the number of code division multiplexing groups that do not support DMRS and data multiplexing, the first DMRS port index is the index of the scheduled DMRS port, the number of first code division multiplexing groups is an integer greater than or equal to 4 and less than or equal to Q, the number of first DMRS port indices is at least one, and the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 4Q-1; DMRS is received or sent according to the first instruction information and the second instruction information.

2. The method according to claim 1, characterized in that, The second indication information is carried in the downlink control information (DCI). The second indication information is an antenna port field, which indicates a first index value. The first index value corresponds to the number of the first code division multiplexing groups and the first DMRS port index.

3. The method according to claim 1 or 2, characterized in that, When the maximum length of the DMRS is 1, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 2Q-1.

4. The method according to claim 1 or 2, characterized in that, When the maximum length of the DMRS is 2, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 4Q-1.

5. The method according to claim 3 or 4, characterized in that, The code division multiplexing group to which the first DMRS port index belongs is the scheduled code division multiplexing group. The scheduled code division multiplexing group is included in the Q code division multiplexing groups. The index value of the scheduled code division multiplexing group is an integer greater than or equal to 0 and less than or equal to Q-1.

6. The method according to any one of claims 1-5, characterized in that, The step of receiving or sending DMRS according to the first indication information and the second indication information includes: The time-frequency resources and DMRS sequence corresponding to the DMRS are determined based on the first indication information and the second indication information; The DMRS sequence is received or transmitted on the time-frequency resource.

7. The method according to claim 6, characterized in that, The DMRS sequence on the time-frequency resource and the time-frequency resource respectively satisfy: k=2*Q*n+k′+Δ k′=0,1 n = 0, 1, ... j = 0, 1, ..., υ-1 Among them, the This refers to the DMRS sequence on the time-frequency resource; The k represents the subcarrier index in the time-frequency resource; The l represents the orthogonal frequency division multiplexing (OFDM) symbol index in the time-frequency resources; The p j Indicates the index of the antenna port; μ represents the subcarrier spacing; The Represents the power scaling factor, the It is related to the number of the first code division multiplexed groups; The w f (k′) represents the frequency domain orthogonal mask (OCC); The w t (l′) represents the time-domain OCC; The r(2n+k′) represents a pseudo-random sequence; The Indicates the starting DMRS symbol index; The l′ represents the relative index of the DMRS symbol; v represents the number of the first DMRS port indexes; The △ represents the subcarrier offset factor; Q represents the number of code division multiplexing groups supported by DMRS configuration type 2.

8. The method according to claim 7, characterized in that, The satisfy: Wherein, P represents the number of the first code division multiplexed groups.

9. The method according to claim 7 or 8, characterized in that, The first DMRS port index corresponds to △, and the w f (k′) and the w t (l′); the △ is an integer greater than or equal to 0 and less than or equal to 2*(Q-1), and the different DMRS ports within the code division multiplexing group to which the first DMRS port index belongs are orthogonal.

10. A communication method, characterized in that, include: Send a first indication message, which is used to indicate the number Q of code division multiplexing groups supported by configuration type 2 of demodulation reference signal DMRS, wherein Q is an integer greater than 3; Send a second indication message, which is used to indicate the number of first code division multiplexing groups and the first DMRS port index, wherein the number of first code division multiplexing groups is the number of code division multiplexing groups that do not support DMRS and data multiplexing, the first DMRS port index is the index of the scheduled DMRS port, the number of first code division multiplexing groups is an integer greater than or equal to 4 and less than or equal to Q, the number of first DMRS port indices is at least one, and the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 4Q-1; The first indication information and the second indication information are used to receive or send DMRS.

11. The method according to claim 10, characterized in that, The second indication information is carried in the downlink control information (DCI). The second indication information is an antenna port field, which indicates a first index value. The first index value corresponds to the number of the first code division multiplexing groups and the first DMRS port index.

12. The method according to claim 10 or 11, characterized in that, When the maximum length of the DMRS is 1, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 2Q-1.

13. The method according to claim 10 or 11, characterized in that, When the maximum length of the DMRS is 2, the value of the first DMRS port index is an integer greater than or equal to 0 and less than or equal to 4Q-1.

14. The method according to claim 12 or 13, characterized in that, The code division multiplexing group to which the first DMRS port index belongs is the scheduled code division multiplexing group. The scheduled code division multiplexing group is included in the Q code division multiplexing groups. The index value of the scheduled code division multiplexing group is an integer greater than or equal to 0 and less than or equal to Q-1.

15. A communication device, characterized in that, It includes a unit or module for performing the method as described in any one of claims 1-9, or it includes a unit or module for performing the method as described in any one of claims 10-14.

16. A communication device, characterized in that, The device includes a processor and an interface circuit. The interface circuit is used to receive signals from other communication devices besides the communication device and transmit them to the processor, or to send signals from the processor to other communication devices besides the communication device. The processor is used to implement the method as described in any one of claims 1-9, or to implement the method as described in any one of claims 10-14, through logic circuits or execution code instructions.

17. A computer-readable storage medium, characterized in that, The storage medium stores a computer program or instructions, which, when executed by a communication device, implement the method as described in any one of claims 1-9, or the method as described in any one of claims 10-14.

18. A computer program product, characterized in that, Includes computer program code, which, when run on a computer, implements the method of any one of claims 1-9, or implements the method of any one of claims 10-14.

19. A communication system, characterized in that, The device includes a terminal and an access network device, wherein the terminal is used to perform the method of any one of claims 1-9, and the access network device is used to perform the method of any one of claims 10-14.

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